On 25/03/2013 Cliff wrote:>The way it was worded, anyone who considers>themselves a climber can be judge and jury and CHOP an anchor. Doesn't>seem like a good strategy for collaboration.

You'll notice that it seems to be ok for anyone who considers themselves a slackliner to place bolts........it's symmetry, dude. If you chop their slacklines into little pieces at the same time, they'll get the message.

>If properly>placed highline bolts are inappropriately chopped by some numbie climber>this will just create more problems.

Again, you're having trouble with the symmetry thing. Somehow you see chopping ok bolts as being worse than placing bad bolts, whereas the two actions are symmetrical. The only difference is that one action has occurred (and will continue to occur), whereas the other has not occurred because of the type of hand wringing which you are demonstrating.

The actual workable solution to this is simple and obvious. Any highliners who want to place bolts need to go and talk to some local climbers and run the plan by them first. Not to ask permission (which would imply ownership and shit), but just as a polite and sensible way to acknowledge that; a) climbers know a lot of relevant stuff about arapiles which highliners do not, and b) climber got there first (by 50 fuching years!). If they want to move onto someone else's turf, the onus is on them to keep relations smooth.

Now, are the slackliners going to do the right thing? Maybe, but they'll probably need a bit of a nudge at the start to help them make sensible decisions.

On 25/03/2013 Dr Nick wrote:>Kieranl:>>Too tired to work out resultant vectors at this time of night.>>Assuming a 30m horizontal slackline and 2m of drop in the middle, 80kg>person in the middle. Downward force is 800N (I'm too lazy to use 9.8 tonight).>It's been too long since I've been down to Arapiles to picture the distances>involved, but I have a feeling we're talking some decent gaps. In any case,>the angles seem to be about what I've seen in slacklines - they're not>*that* slack.>>Load angle is about 8 degrees below horizontal. That comes to about 3kN>(300kg equivalent) on the anchors. If you drop it to 1m of slack then it's>about 6kN on each anchor, and 0.5m gives 12kN. Shorter lines for the same>slack give lower loads. >>Note that these are the generated loads, and are going to be static. There's>no safety factor, and nothing taken into account for bounce loads. If you>take a reasonably conservative 4 fold multiplier for those, you're getting>up to the breaking strain of a lot of natural gear even for the best case>scenario. >>I suppose if you had a belayer on each side with enough slack that you>weren't going to generate huge loads you could test things, but I can see>the attraction in multiple BFO bolts, particularly if the slack line is>going to be your safety line as well.>>
I'm not going to claim any expertise on physics, but, these guys safety is a normal climbing harness with a single sling/short bit of rope and biner onto the slack line. Surely this is the weak point in the system, not a decent multipoint equalised gear anchor? Either that, or the person's body - aren't they going to fracture their pelvis/perforate a kidney or something else exciting at loads of 12 kn?

On 25/03/2013 One Day Hero wrote:>On 25/03/2013 kieranl wrote:>>>2. Anchors placed for climbing and abseiling are never used for rigging>>highlines due to the risk of compromising the strength of the anchors.>>Why? Highlining won't damage bolts unless they do something crazy. Bolts>which have been damaged to the point where they are liable to fail under>bodyweight will look damaged. I didn't notice anything at all on the Missing>Link rap bolts which were used for a slackline.>>>>.* Note that natural anchors suitable for climbing anchors may not be>>suitable for highline anchors.>>Slacklines don't generate end of the world forces. Should stop pandering>to the slackliner notion that they need 16mm bolts for their nonsense.>There's no good reason why they shouldn't build natural anchors when available.>>5. Total 'tards who haven't ever seen a nut or cam, have never drilled>a hole in rock, don't know their earhole from a bolthole, should not be>bringing a drill to Araps to "work out how to do it".

I usually agree with you on bolting, but in this case I don't mind a few slackline specific bolts for the following reasons:

- The forces generated are higher than you think and trad gear is not rated for them. I haven't checked Dr Nicks calcs but they sound about right. Now, I'm a trad climber from years back, but I wouldn't trust trad gear for my only safety line when the potential forces generated are equal to the failure rating of my gear (~12kN).

- If the bolts interfere with existing routes it is purely incidental.

- The number bolts is limited by the number of places suitable for high lines.

For these reasons I support the installatioin of a small number of bolts for highlines

It would be safe to use rap anchors where convenient, as rap bolt damaged enough to fail under the body weight of an abseiler, will fail due to the slackline first. It would just be annoying for climbers to wait until the anchor is free.

On 26/03/2013 Climboholic wrote:>It would be safe to use rap anchors where convenient, as rap bolt damaged>enough to fail under the body weight of an abseiler, will fail due to the>slackline first. It would just be annoying for climbers to wait until the>anchor is free.

Given the tendency for lines to be left rigged for days (maybe weeks?) at a time, you could be waiting a long fricking time. For that reason alone they should be using their own anchors.

>>I usually agree with you on bolting, but in this case I don't mind a few>slackline specific bolts for the following reasons:>>- The forces generated are higher than you think and trad gear is not>rated for them. I haven't checked Dr Nicks calcs but they sound about right.>Now, I'm a trad climber from years back, but I wouldn't trust trad gear>for my only safety line when the potential forces generated are equal to>the failure rating of my gear (~12kN).

Isn't that for 1 piece of gear? If that load is equalised over 4, or more if you were worried about it, then it's not failure load?>>- If the bolts interfere with existing routes it is purely incidental.

Couldn't you say that about any new bolt placed? But people jump up and down about bolts that are anywhere near an existing route? For example, the carry on about the one on Give me Convience or Give me Death?>>>- The number bolts is limited by the number of places suitable for high>lines.

You could develop a hankering for myriad high lines. Why not Fang to Alis? Dminor to Stentor? Lizard to Pilot error? Across Yesterday gully, Mysteries gully, high dive gully? on top of the few i mentioned earlier. It's not that limited.>

On 26/03/2013 Wendy wrote:
[SNIP] these guys safety>is a normal climbing harness with a single sling/short bit of rope and>biner onto the slack line. Surely this is the weak point in the system,>not a decent multipoint equalised gear anchor? Either that, or the person's>body - aren't they going to fracture their pelvis/perforate a kidney or>something else exciting at loads of 12 kn?

Two things Wendy:
1: Everyone I've seen uses rope and a rap ring for their safety. There's no cross loading and it's much stronger.
2: Slacklines stretch. If they ever actually get on the damned things, watch how much it bounces whenever they fall off (it's not a factor 2!). And (here's the fun bit), they're only experiencing the downwards portion of the force, whereas the anchor gets the horizontal, which in this scenario is much bigger (It's a force triangle, not just a force line).

On 26/03/2013 ajfclark wrote:>On 26/03/2013 Climboholic wrote:>>It would be safe to use rap anchors where convenient, as rap bolt damaged>>enough to fail under the body weight of an abseiler, will fail due to>the>>slackline first. It would just be annoying for climbers to wait until>the>>anchor is free.>>Given the tendency for lines to be left rigged for days (maybe weeks?)>at a time, you could be waiting a long fricking time. For that reason>alone they should be using their own anchors.

>2: Slacklines stretch. If they ever actually get on the damned things,>watch how much it bounces whenever they fall off (it's not a factor 2!).>And (here's the fun bit), they're only experiencing the downwards portion>of the force, whereas the anchor gets the horizontal, which in this scenario>is much bigger (It's a force triangle, not just a force line).

Oh no, not a force triangle! Actually, the triangle is in your head owing to your perfectly natural desire to keep your head level and assign x and y coordinates to match. If you just tilt your head it will become apparent that the imagined "force triangle" is simply a slopey force line, which is much less dangerouser.

>That's exactly what I'm saying, but the safety argument is bs.
Which safety argument is BS?
Rap anchors aren't placed as highline anchors and some may fail if used as such. That's a safety issue. I count the death of a slack-liner as being of equal significance as the death of a climber.
If a rap anchor is used for a highline and is distorted, without breaking, the anchor is compromised. It's probably going to hold abseiling, I've seen some shocking bolts that people have taken hanging belays or abseiled from. But the anchor is compromised. It's a safety issue, it's not BS.
Until someone like Mikl or the guys at the rope test lab to do a bunch of tests and put some numbers to it that prove otherwise, it's a safety issue.
Most people, in my experience, just blindly trust the fixed gear. There is a general assumption that if it must be safe because otherwise "they" would have replaced it.

>I'm not going to claim any expertise on physics, but, these guys safety>is a normal climbing harness with a single sling/short bit of rope and>biner onto the slack line. Surely this is the weak point in the system,>not a decent multipoint equalised gear anchor? Either that, or the person's>body - aren't they going to fracture their pelvis/perforate a kidney or>something else exciting at loads of 12 kn?

Someone's already chimed in, but it comes down to where the load is. The harness has to catch maybe double body weight by the time there's bounce from a relatively small fall onto the sling. The anchors have to take that load as a sideways force that's balanced by the other anchor, with a bit of that being the angle of the slackline pulling the person back up.

It's the same reason it's not good to have a trad anchor too far apart - the angle between the pieces actually sets up an opposing force that increases the load hugely. In this case it's a roughly bodyweight load rather than a falling climber, but rather than having about 30 degrees between the anchors you've got about 170, so the load is bloody huge!

Well, it's more in the head of my old lecturers, Cartesian geometry's not that natural a desire for anyone. Really though, it's two force lines at an angle to each other (one along the slackline, one along the safety). Which is deliberately obtuse, a bit like your good self.

Let it be said that Prohibition in this context never works, especially with adventurous types like climbers and highliners.

is anyone talking to the highliners about this?

I believe high lining is still young and new. So you are getting your a rag tag group of dudes and dudettes taking ever opportunity to explore their passion, just like the climbing community was decades ago right?

There must be some association or group that is responsible for monitoring/tracking all the routes that are currently bolted in araps. Wouldn't it be smarter and safer to work with highliners and getting good infrastructure setup and maintained.... and perhaps more importantly getting that information publicized? Just like climbers have established central resources.

I think this will ensure the responsible installation of infrastructure, minimise impact on the rock, and maximise safety for everyone.

The video that won the judges vote at Goastfest was effectively a reply form the slackliners about their bolting practices and the sport in general and alluded to this thread. The final line was something like "We feel the bolting was absolutely necessary".

So in one sense the message regarding climbers concerns is reaching at least some individuals in that community which means there is possibility of dialogue occurring. Did anyone get a chance to speak to Sam (I believe that was his name) or other members of that group?